Ulster Bank said it has put aside €103m for costs associated with its "technology incident" earlier this year.
The bank said this provision covers all operational costs associated with the incident, as well as redress of €52m to 750,000 customers across Ireland.
"As we continue to deal with customer claims and costs associated with the incident, we expect that there will be some additional costs to the bank over the coming months," it said today.
Ulster Bank is owned by Royal Bank of Scotland, which reported a pre-tax loss of £1.3 billion, compared to a £2 billion profit the same time last year.
Ulster Bank also today reported an operating loss of €306m for the three months to the end of September.
The bank said its impairment losses remained high and they rose marginally to €415m in the third quarter from the same time last year.
It noted that the losses were mainly in its residential mortgage portfolio and said that mortgage arrears continue to rise as unemployment remained high and "affordability issues" persisted.
"The market remains difficult and we continue to see an elevated level of mortgage arrears," Ulster Bank's chief executive Jim Brown said.
"We continue to work with our customers who are in financial difficulty on an individual basis to offer them appropriate support initiatives.
"We also continue to actively encourage our customers to contact us if they have any concerns about their financial health or are experiencing financial difficulty."
Ulster Bank said that customer deposits remained flat in the third quarter compared to the second, and said it did not see a significant outflow of money after its technology glitch.
It added that retail and SME balances increased marginally in the three-month period.
On an annual basis, loans to customers fell by 3% due to weak customer demand. Customer deposits declined by 8% due to outflows of wholesale balances due to market volatility and the impact of a rating downgrade in the second half of 2011.
The bank reported a third quarter operating profit - before impairment charges - of €110m, up 12% on the previous quarter.
It said this was as a result of solid income performance in the quarter and lower expenses.
Expenses fell by €3m over the three months as the implementation of cost management initiatives continued to progress.